#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<math.h>

int main()
{

	int m;
	float n;
	int i = 0;
	while (scanf("%f%d", &n, &m) != EOF)
	{
		float sum = n;
		for (; m-1; m--)
		{
			sum += (float)sqrt(n);
			n = sqrt(n);
			i++;
		}
		printf("%.2f\n", sum);
	}
	return 0;
}